Simultaneous Synergy in CH4 Yield and Kinetics: Criteria for Selecting the Best Mixtures during Co-Digestion of Wastewater and Manure from a Bovine Slaughterhouse

Zamir Sánchez,Davide Poggio,Humberto Escalante,Liliana Castro

doi:10.3390/en14020384

Zamir Sánchez, Davide Poggio + Show 2 more

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https://doi.org/10.3390/en14020384

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Abstract

Usually, slaughterhouse wastewater has been considered as a single substrate whose anaerobic digestion can lead to inhibition problems and low biodegradability. However, the bovine slaughter process generates different wastewater streams with particular physicochemical characteristics: slaughter wastewater (SWW), offal wastewater (OWW) and paunch wastewater (PWW). Therefore, this research aims to assess the anaerobic co-digestion (AcoD) of SWW, OWW, PWW and bovine manure (BM) through biochemical methane potential tests in order to reduce inhibition risk and increase biodegradability. A model-based methodology was developed to assess the synergistic effects considering CH4 yield and kinetics simultaneously. The AcoD of PWW and BM with OWW and SWW enhanced the extent of degradation (0.64–0.77) above both PWW (0.34) and BM (0.46) mono-digestion. SWW Mono-digestion showed inhibition risk by NH3, which was reduced by AcoD with PWW and OWW. The combination of low CH4 potential streams (PWW and BM) with high potential streams (OWW and SWW) presented stronger synergistic effects than BM-PWW and SWW-OWW mixtures. Likewise, the multicomponent mixtures performed overall better than binary mixtures. Furthermore, the methodology developed allowed to select the best mixtures, which also demonstrated energy and economic advantages compared to mono-digestions.

Highlights

The global meat industry consumes 24% of the total water used for food and beverage production. [1]
The slaughter bovine process varies depending on the available technologies; in general, it consists of four stages and generates similar wastewater streams: (i) cattleyard wastewater (CWW), generated from the preliminary washing of livestock and yards, containing urine and feces; (ii) slaughter wastewater (SWW), which contains blood, rich in protein; (iii) paunch wastewater (PWW), generated in the removal of the digestive tract content, with structural carbohydrates in the form of lignocellulosic material; (iv) offal wastewater (OWW) from the cleaning of the white viscera, containing particles of meat and fat
The first group includes the substrates with lignocellulosic nature, namely the Paunch Wastewater (PWW) and Bovine Manure (BM), which had low

Summary

Introduction

The global meat industry consumes 24% of the total water used for food and beverage production. [1]. The global meat industry consumes 24% of the total water used for food and beverage production. Beef production has one of the largest water footprints among all foods (15,400 m3 t−1 of meat) [2]. Animal slaughter and meat processing are the main contributors to the footprint, in terms of water use and wastewater generation. Slaughterhouse wastewater volumes have been reported to be between 0.57 m3 bovine−1 [3] and. 4.22 m3 bovine−1 [4]. These wastewaters are characterized by a chemical oxygen demand (COD) between 2000 mg L−1 [5] and 20,400 mg L−1 [6]. The slaughter bovine process varies depending on the available technologies; in general, it consists of four stages and generates similar wastewater streams: (i) cattleyard wastewater (CWW), generated from the preliminary washing of livestock and yards, containing urine and feces; (ii) slaughter wastewater (SWW), which contains blood, rich in protein; (iii) paunch wastewater (PWW), generated in the removal of the digestive tract content, with structural carbohydrates in the form of lignocellulosic material; (iv) offal wastewater (OWW) from the cleaning of the white viscera, containing particles of

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